KR20120049323A - Method of providing telecommunications network security - Google Patents

Abstract

The present invention provides a method for providing network security within a mobile wireless communications network, the method comprising generating a security context for communication between the mobile wireless communications device and the network, the security context being input such as a downlink NAS count. Generated in response to the parameter, and the method may be configured to apply a version of the parameter different from the previous version, such as, for example, an incremented downlink NAS count, as part of each initial handover attempt separately from the network signaling message. It further comprises the step of controlling.

Description

How to Provide Telecommunications Network Security {METHOD OF PROVIDING TELECOMMUNICATIONS NETWORK SECURITY}

Priority claim

Priority is claimed by British Patent Application No. 0913909.8, filed August 10, 2009, and British Patent Application No. 0919398.8, filed November 5, 2009, the contents of which are incorporated herein by reference.

Technical field

The present invention relates to a telecommunications network security and related method and devices configured to provide the same.

As mobile communication network technology evolves and high performance networks and systems become available, mobile wireless communication devices used, such as known mobile equipment (ME) and user equipment (UE), for different radio access technologies (RAT) It possesses the capability and thus tends to allow handover procedures at both inter-RAT and intra-RAT bases.

High security and integrity is an ongoing requirement for mobile communication networks, and in particular, it is desirable to prevent interception of communication messages.

Security often evaluates current usage keys, such as Ciphering Key (CK) and Integrity Key (IK), and the generation of these keys often occurs during handover procedures.

It is noted that limitations and shortcomings exist in the operation and management of these security issues and may result in compromise in potential security.

Known procedures for the generation and management of security keys are disclosed in US Patent Publication Nos. 2009/161874 A1 and 2009/154703 A1, Canadian Patent Application No. 2659959 A1 and US Pat. No. 7519178 B1, which are enhanced in comparison with the present invention. And a completely different solution to the problem of security.

The present invention seeks to provide a method for establishing network security that has advantages over such known method and network elements and associated mobile wireless communication network elements.

According to a first aspect of the present invention, there is provided a method for providing network security within a mobile wireless communications network, the method comprising creating a security context for communication between a mobile wireless communications device and a network, the security context. Generating the security context, wherein the security context is generated in response to an input parameter; And as part of each initial handover attempt, controlling the parameter to apply a version of the parameter that is different from the previous version.

As long as the method of the exemplary embodiment of the present invention is used during the initial handover attempt of each handover procedure and ensures that the input parameters for use in determining the security context differ from the previous input parameters, For example, one can prove advantageous in ensuring that legacy parameters are not inadvertently used to generate the necessary security keys.

In one example, control of the parameter does not depend on network signaling for at least one handover attempt.

Preferably, the control of the parameter may be configured not to rely on signaling from the network to the mobile wireless communication device for at least one handover attempt.

In particular, the signaling may preferably include Non-Access Stratum (NAS) messaging.

Advantageously, the input parameter may comprise a signal count and in particular a downlink (DL) NAS count.

Preferably, the method comprises controlling a parameter for each initial handover attempt.

In an exemplary embodiment, the method can further include monitoring for the success of the handover attempt.

Advantageously, the handover attempt may be repeated with the same parameter if it is determined that the initial handover attempt was not successful.

Advantageously, further attempts at the handover may be allowed only if a failure is indicated in the ongoing attempt.

Preferably, success may be determined by receipt of a handover command by the mobile wireless communication device.

Advantageously, the indication of the handover failure may comprise a non NAS forwarding indication.

Advantageously, this non-NAS forwarding indication may be configured to be sent if the parameters are indicated not to be received by the mobile wireless communication device.

 Preferably, the method may include sending an inter-radio access technology (IRAT) handover that includes a predetermined value of the downlink NAS count while indicating that the mobile wireless communication device has not received a count.

Preferably, the method includes not incrementing the count once a RAT handover for a Universal Mobile Telecommunications System (UMTS) message has been sent.

Advantageously, the method may comprise performing a routing update procedure at the mobile wireless communications device in response to determining that the count was used in a previous handover, in particular in the immediately preceding handover.

Advantageously, the update procedure may include information about key set availability so that the network can perform the authentication procedure.

In an exemplary embodiment, these additional features are particularly true because the radio access network (RAN) of a Long Term Evolution (LTE) system is a mobile wireless communication device because a layer 2 acknowledgment message from the UE was not received by the RAN LTE. It can be used in scenarios that clearly indicate that no count has been received.

Furthermore, these characteristics can preferably be used in particular in connection with handover to UMTS where the key set identifier includes the UMTS key set identifier, so that the network can perform the UMTS authentication procedure.

According to another aspect of the invention, a method is provided for providing network security within a mobile wireless communications network, the method comprising: creating a security context for communication between a UE and the network, the security context being a downlink NAS count; Creating the security context, generated in response to the; And as part of each initial handover attempt, increasing the DL NAS count to distinguish from the previous count value.

As will be appreciated, exemplary embodiments of the present invention may preferably be provided to enhance handover procedures for UMTS, and in particular handover procedures from Long Terminal Evolution (LTE) systems.

Exemplary embodiments of the invention may prove particularly useful with regard to continuous handover from LTE to UMTS.

According to another aspect of the invention, a mobile wireless communications network element for operation within a mobile wireless communications network is provided and configured to provide a security context for communication between a mobile wireless communications device and a network, the network element being a security context. Is generated in response to the input parameter, wherein as part of each initial handover attempt, the network device is configured to control the parameter to apply a version of the parameter that is different from the previous version.

Thus, an exemplary embodiment of the present invention may provide a mobile wireless communications network element that exhibits the functionality of various features of the method as defined above.

That is, the element may preferably ensure that the input parameters as used for use in determining the security context and during the initial handover attempt of each handover procedure are never the same during successive handovers, which is an example. For example, it may prove advantageous to ensure that legacy input parameters are not used by chance when generating the necessary security keys.

In addition, in the exemplary embodiment, the control of the parameter does not have to rely on signaling for at least one handover attempt in the handover procedure then the signaling may include signaling from the network to the mobile wireless communication device. have.

In addition, for the network element, the signaling may preferably comprise non-access stratum (NAS) messaging and the input parameter may preferably comprise a signal count, in particular a downlink (DL) NAS count.

As above, the element may preferably include a control function such that if it is determined that the initial attempt failed, the handover attempt is repeated with the same parameters.

Advantageously, the control function may comprise initiating a routing update procedure at the mobile wireless communication device in response to determining that the count was used in a previous handover and in particular in the immediately preceding handover.

As above, the update procedure may preferably include information regarding key set availability so that the network may perform the authentication procedure.

In an exemplary embodiment, these additional features are preferably radio of the Long Term Evolution (LTE) system that the mobile wireless communication device did not receive a count because a layer 2 acknowledgment message from the UE was not received by the RAN LTE. It can be used in scenarios in which the access network (RAN) is not obvious.

In addition, these characteristics can preferably be used in connection with a handover to UMTS where the key set identifier includes the UMTS key set identifier, so that the network can perform the UMTS authentication procedure.

According to a particular feature of one embodiment, an "initial" handover from an LTE command message from an LTE core network may include an increased downlink NAS count compared to the current count. This increased downlink NAS count is pre-forwarded to the UMTS core network with a forward relocation request during the Inter Radio Access Technology (IRAT) handover preparation phase.

If the handover from the LTE command message including the NAS security parameters was not correctly received by the UE, the NAS non-delivery indication message may preferably be sent by the eNB to the LTE core network.

The LTE core network may preferably be configured not to send any additional handover from the LTE command message to the UE if a NAS non delivery indication message was not received from the LTE radio access network (eNodeB, eNB).

In order to prevent downlink NAS count asynchronousization between the UE and MME, and if a NAS non-delivery indication has been received from the eNB, the LTE core network preferably has the same downlink NAS count as the previously transmitted (ie not incremented). It may be configured to retransmit the same NAS security container containing.

From the above, the LTE core network knows that upon receipt of Forward Relocation Complete, the UE preferably used the downlink NAS count as included in the handover from the LTE command sent to the UE.

For example, with respect to LTE network side components, the eNB is preferably configured to send a NAS non-delivery indication comprising a NAS security container to the LTE core network if a handover from the LTE command message was not received by the UE. Can be.

With respect to MME, the downlink NAS count may be incremented only in the "initial" transmission of handover from the LTE command. Of course, in case of transmission failure of handover from LTE command, the MEE may be configured to retransmit the same previous NAS security included in the NAS PDU IE, preferably via the eNB to the UE.

In an exemplary embodiment, a radio access network (RAN) from a Long Terminal Evolution (LTE) system indicates that the mobile wireless communication device did not receive a count because a layer 2 acknowledgment message from the UE was not received by the RAN LTE. In the case of ambiguity, if the count is detected as being pre-used on a previous handover to UMTS for continuous handover to UMTS, then the mobile wireless communication device may use no available network to perform the UMTS authentication procedure. Performs a routing area update procedure including the information of the UMTS key set identifier.

As will be appreciated, exemplary embodiments of the present invention may be applicable, in particular if ISR is activated on IRAT handover from LTE, but may generally be applicable to any IRAT handover from LTE.

Exemplary embodiments of the invention may also provide for a mobile wireless communications device configured to operate within a network and with a secure context.

The invention is further described below by way of example only with reference to the accompanying drawings.
1 is a schematic diagram of successive handovers illustrating the limitations of current technology.
2 is a signaling diagram for handover examples in accordance with one embodiment of the present invention and related to LTE and UMTS core networks.
3 is a schematic diagram of a wireless communication network element in accordance with an embodiment of the present invention.

As will be understood, an exemplary embodiment of the present invention further relates to the use of decryption keys and integrity keys generated in response to input parameter downlink NAS counts and in particular with respect to the provision of security context for LTE and UMTS systems. Discussed and described with reference to the accompanying drawings.

Certain disadvantages of the current technology arise with regard to the manner in which such security contexts are developed especially for continuous handover and will be discussed in more detail below.

As noted, the security context generally includes a ciphering key used to ensure data confidentiality, and an integrity key used to ensure that no alteration of data occurs during its transmission between two communication parties. do.

As one example, a UMTS security context can be created between a UE and a network to provide secure access to a UMTS system, and likewise, an LTE security context can be created between a UE and a network for access to an LTE system. .

In addition, an access layer security context may be created for each UMTS or LTE security context to ensure that security is maintained with respect to the relevant layer of the protocol stack.

As noted, and especially within an inter-RAT environment, the UE can move from LTE to UMTS in connected mode and in this scenario, and the UMTS security context is derived from the preceding LTE security context. The input parameter of the LTE security context may include, for example, downlink NAS count.

Of course, it is understood that the downlink NAS count is incremented each time the network sends a NAS message to the UE.

Thus, in a scenario where the UE performs consecutive handovers from LTE to UMTS, and the network does not send any NAS message to the UE, it is understood that the same UMTS security context is then reused.

The absence of a NAS message from the network from the UE may be initiated when the Idle Mode Signaling Reduction (ISR) feature is activated, for example.

This potential hazard in security is also described with reference to FIG. 1. Here, the initial connection to the LTE system 10 is indicated first, followed by a handover to the UMTS 12, then a return to the LTE system 14 and a back handover to the next UMTS 16. .

First, upon initiating an initial connection to LTE 10, a current LTE security context is developed and includes a decryption key and an integrity key.

Upon movement of the UE as shown by arrow A in the mode connected with UMTS 12, the UMTS security context with decryption key and integrity key then uses the downlink NAS count as input parameter and the LTE (10). Generated as a result of the mapping from the security context of.

In the illustrated scenario, the UE then moves to the LTE system 14 in idle mode as shown by arrow B, and again uses pre-generated security context mirroring on the previous move to LTE 10.

However, more importantly, in a scenario where there is an activation 18 of ISR features for a UE (not shown), no NAS signaling from the network to the UE is thereafter such that there is no increment in the value of the downlink NAS count. Is sent.

Thus, on the next consecutive movement of the UE to UMTS 16 as indicated by the arrow C in the connected mode, the UMTS security context with decryption key and integrity key is associated with the previous move to UMTS 12. It is generated as a result of the use of the same downlink NAS count and mapping from the LTE security context as used. Thus, the same security keys are used in connection with the move to UMTS 16 even for the move to UMTS 12. Of course, if a third party "attacker" who wishes to block communication can access the keys from the previous move at the UE of the UMTS, the "attacker" reuses these keys in the next UE move to the UMTS 16. The blocking of communication between the UE and the network can then, of course, indicate a substantial breach in security.

As understood from the previous discussion and certainly from the following illustrated examples, the present invention is that the input parameter, the downlink NAS count in the illustrated example, may not remain the same between successive handovers, so that the attacker is UE Having keys to UMTS from a previous move of may prove advantageous in ensuring that it will not be for any subsequent communication exchange.

In addition to the aforementioned prior art documents, various known attempts have been made to improve these security issues. For example, to use an uplink NAS count to derive a UMTS security context; To use AS Next (Next Hop) and NCC (Next Chain Count) security parameters to generate different AS keys; Use of NAS Nonce UE and Nonce MMW security parameters; Attempts have been made to use downlink NAS messages from the network and to execute NAS secure mode command procedures. However, both of these examples suffer from limitations as long as they affect both the UE and the network, and in some examples are limited by backward compatibility issues.

Referring now to FIG. 2, a signaling diagram illustrating an embodiment of the present invention is provided, covering scenarios where a handover command was not received by the UE and a scenario where a handover command was not received by the UE.

2 shows in schematic form a network arrangement for a UE 20 and an eNB 22 of its access network, and a network element comprising an LTE core network 24 and a UMTS core network 26. Thus, the illustrated embodiment is understood to relate to continuous handover from an LTE system to a UMTS system.

The illustrated procedure is initiated from the handover preparation phase 28 in which the “requested handover” signaling message 36 is sent from the eNB 22 to the LTE core network 24, according to this embodiment a downlink NAS. A controlled increase in count begins at 38. Thereafter, the forward communication request signal 40 from the LTE core network 24 to the UMTS core network 26, and the forward communication response 42 transmitted therefrom are based on the increased downlink NAS count and the LTE network 24. Consider both the UMTS security context and the UE identity mapped from.

Thus, as will be appreciated, this controlled incremental change in the downlink NAS count may be applied to any preceding hand so that, while the handover is prepared, the security context and thus associated security keys avoid potential harm in security. It ensures that it is different from what happens with the over.

Following completion of the handover preparation phase 28, the signaling related to the handover execution phase 30 initiates a handover command 44 from the LTE network 24 to the eNB 22. As will be understood below, according to the illustrated handover procedure, if a "NAS non delivery indication" message has not been received from the LTE radio access network eNB, the UE 20 from the LTE core network 24 is received. No additional "handover command" message is sent, and importantly and as described below any such retransmissions use the same downlink NAS count as previously incremented during the handover preparation phase 28 described above.

Two scenarios occur during each of the handover execution phases 30 and those shown in FIG. 2.

In the first scenario 32, the handover command is not successfully received by the UE 20. However, as described above, the handover command signal 44 does not exist but rather the NAS non-delivery indication signal 46 is transmitted from the eNB 22 to the LTE core network 24.

This particular signaling message 46 is an important step in the method of implementing the present invention as long as the LTE core network 24 retransmits the handover command signal 48 only upon receipt of this signaling message 46. Importantly, the retransmitted handover command 48 uses the same NAS security container that includes the same downlink as the pre-transmitted NAS count, which is advantageously a network element of a core network such as a mobile management entity (MME). And downlink NAS count synchronization between the UE and the UE 20.

In another scenario 34, the handover command signal 44 is a UE as indicated by the command message 50 and subsequent handover from the UE 20 to the UMTS completion message 52 delivered to the UMTS radio access network. Is successfully received by This then initiates a communication complete signaling message 54 to the UMTS core network 26. The UMTS core network 26 responds to the forward relocation complete signaling message 56 to the LTE core network 24.

Advantageously, upon receipt of this forward relocation complete signaling message 56, the LTE core network may increment the downlink NES count as included in the “handover command” sent by the UE 20 to the UE 20. Can easily be determined. This serves as a reassurance that no security risks occur with respect to the establishment of the security key and associated security context.

As will be appreciated, during any subsequent handover preparation phase for subsequent LTE to UMTS handover, the downlink NAS count is then incremented to avoid reuse of the previous downlink NAS count, Functions like an input parameter for decision.

Thus, security risks such as those encountered in the current technology can be advantageously prevented.

As will be appreciated and with particular reference to the illustrated embodiment, the present invention advantageously provides a signaling message that includes a NAS delivery indication if the NAS security parameters have not been received by the UE. In addition, the IRAT handover to the UMTS signaling message containing the predetermined value of the downlink NAS count continues until the reception of the UE occurs, so that the count is not incremented once the IRAT handover is sent to the UMTS message. This allows for example to maintain synchronization between the UE and the MME.

Finally, referring to FIG. 3, a simple schematic diagram of a network element that implements the present invention and forms part of a network device, such as MME 58, is provided. The MME 558 is configured to include a control function 60 for increasing the downlink NAS count on the "initial" transmission of the handover, for example from an LTE command, and determining the failure of delivery of the handover from the LTE at the UE. And an associated control function 62, which serves to initiate retransmission of the same NAS security container at the time. As such, control element 60 transmits only the non-incremental downlink NAS count after determination of the failure of the previous transmission to the UE. Of course, and as described above, if the transmission of the handover command to the UE is successful, in the next case of the initial stage of the additional handover procedure, the control function 60 again occurs between two consecutive handover procedures. Increment the downlink NAS count regardless of the actual state of downlink NAS signaling that may have been. If the UE detects that the same or older downlink NAS count is reused, the UE performs a NAS routing area update procedure.

It is to be understood that the present invention is not limited to the details of the foregoing embodiments, but may relate to the control of any suitable security parameters with respect to appropriate handover procedures. In particular, the present invention is applicable to scenarios where ISR is activated on IRAT handover from LTE, but also generally applicable to any IRAT handover from LTE.

Industrial availability

The present invention can be applied to mobile wireless communications between a mobile wireless communications device and a network to provide a high degree of network security within the network.

Claims (19)

A method for providing network security within a mobile wireless communications network,
Generating a security context for communication between a mobile wireless communications device and the mobile wireless communications network, the security context being generated in response to an input parameter; And
As part of each initial handover attempt, controlling the parameter to apply a version of a parameter different from the previous version. The method of claim 1,
Controlling the initial parameter remains independent of network signaling for at least one handover attempt. The method of claim 2,
Wherein the input parameter comprises a signal count. The method according to any one of claims 1 to 3,
Controlling the parameter during each initial handover attempt. The method according to any one of claims 1 to 4,
And if it is determined that the initial attempt was unsuccessful, the handover attempt is repeated with the same parameters. The method of claim 5, wherein
Wherein handover failure is determined by receipt of a Non-Access Stratum non delivery indication by the mobile wireless communications network. The method according to any one of claims 1 to 6,
Storing a different version of the parameter as part of a security context for subsequent handover to UMTS. The method of claim 7, wherein
Detecting the same or older parameters by comparison with the next expected value stored as part of a security context on subsequent handover to UMTS. The method of claim 8,
Wherein the same or older parameter value is detected by a mobile wireless communications device in the mobile wireless communications network. The method of claim 9,
At the mobile wireless communications device, performing a NAS routing update procedure to attempt UMTS reauthentication through the inclusion of a no UMTS key set identifier. The method of claim 5, wherein
Wherein the success is determined by receipt of a handover command by the mobile wireless communications device. The method according to any one of claims 1 to 11,
Controlling the parameter during periods of non-NAS signaling exchange between the mobile wireless communication device and the mobile wireless communication network. The method of claim 12,
Controlling the parameter during periods of idle mode signaling reduction activation. A method for providing network security within a mobile wireless communications network,
Generating a security context for communication between a UE and a network, the security context being generated in response to a downlink NAS count; And
Increasing, as part of each initial handover attempt, a DL NAS count so as to be distinguished from a previous count value. 15. The method of claim 14,
Configuring to enhance the handover procedure to UMTS. A mobile wireless communications network element configured for operation within a mobile wireless communications network and for providing a security context for communication between a mobile wireless communications device and the mobile wireless communications network.
The network element is configured such that the security context is generated in response to an input parameter, and as part of each initial handover attempt, the network device is configured to control the parameter to apply a version of a parameter different from the previous version. Wireless communication network element. 17. The method of claim 16,
The mobile wireless communications network element, configured to provide network security according to the method of any of claims 1-15. A mobile wireless communications device configured for operation within a mobile wireless communications network and configured to operate with a security context created with respect to input parameters.
And the mobile wireless communications device is configured to perform a routing update procedure in response to determining that the input parameter was used in a previous handover procedure. The method of claim 18,
And the update procedure includes information regarding key set availability.

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